Ultrathin Fully Printed Light‐Emitting Electrochemical Cells with Arbitrary Designs on Biocompatible Substrates

Abstract

Organic electronic devices are often highlighted in terms of cost‐efficient solution processing and potential printability. However, few studies are reporting truly full‐solution‐processed devices taking into account the electrodes as well as all other layers. This results in a production method that only partially benefits from the cost efficiency of solution processing and that still depends on costly and elaborate techniques like evaporation and/or lithography. This lack of knowledge is addressed by presenting a truly fully printed light‐emitting electrochemical cell on ultraflexible parylene C substrates usable for conformable electronics. All device parts are fabricated by industrial relevant printing‐techniques under ambient atmosphere. Inkjet printing is used for the structuring of the device layout and is therefore able to implement and create arbitrary designs. Further layers are produced by blade coating which is well suited for the coating of large areas. The devices show stable operation at a luminance higher than 100 cd m−2 for 8.8 h, can reach a maximum brightness of 918 cd m−2, and exhibit a turn‐on time of 40 s to reach 100 cd m−2. Moreover, biocompatible and biodegradable materials are utilized to allow potential applications in life science and bioelectronics.

Recent Progress of Fiber Shaped Lighting Devices for Smart Display Applications—A Fibertronic Perspective

“…With these intrinsic robust, simple, fault‐tolerant features, LECs have been considered as one of the most promising candidates for realizing truly flexible, and wearable display applications . Moreover, intrinsically stretchable LECs have been successfully fabricated by embedding elastomeric polymers, such as polydimethylsiloxane (PDMS) and polyurethane acrylate (PUA) into constituent materials in devices or substrates …”

Inkjet‐Printed Micrometer‐Thick Perovskite Solar Cells with Large Columnar Grains

“…In recent years, research and development of solution‐based scalable coating and printing techniques have attracted significant attention, for example, blade coating, slot‐die coating, and inkjet printing . Inkjet printing stands out among these technologies as a noncontact digital printing technique that offers the freedom of printing arbitrary design patterns at very low material consumption . Inkjet printing is an adaptable and fast printing technique and is used not only in research on, for example, large‐area organic solar cells, but also already in large‐area industrial applications such as next‐generation organic light‐emitting diode production lines .…”

Thermally activated delayed fluorescence with 7% external quantum efficiency from a light-emitting electrochemical cell

“…The light-emitting electrochemical cell (LEC) is such an area-emissive device that can be thin and flexible 6–10 , and recent studies have demonstrated that well-designed LECs, in addition, can be highly efficient at significant luminance 11 , and be fabricated with low-cost and scalable solution-based methods 12–15 . However, for several of the projected high-volume applications it is further desirable if the constituent device materials are sustainable 16–18 , and it is therefore unfortunate that current efficient LECs and organic light-emitting diodes (OLEDs) commonly employ emitters that comprise very rare and expensive metals from the platinum group in the periodic table 19–21 .…”